Protein isolates are products of native, unhydrolyzed proteins, obtained by isolating proteins from a proteinaceous source, usually a proteinaceous vegetable source. Protein isolates are also referred to as protein concentrates or purified protein products. Protein isolates find various industrial utility, primarily in the food industry, e.g., for human and animal nutrition, especially products for human infants and young animals.
Methods of producing protein isolates by use of various hydrocarbon specific enzymes have been described. Thus, U.S. Pat. No. 4,478,856 describes a method for producing purified vegetable proteins, and U.S. Pat. No. 3,958,015 describes a method for concentrating soy proteins.
Protein isolates may also be produced by combining aqueous extraction and membrane isolation techniques. Such methods are described by e.g. Lawhon et al. [cf. e.g. Lawhon J T, Rhee K C & Lusas E W; The Journal of the American Oil chemists Society 1981 58 (3) 377-384; and Lawhon J T, Manak L J, Rhee K C, Rhee K S & Lusas E W; Journal of Food Science 1981 46 (3) 912-916+919]. Also U.S. Pat. No. 4,420,425 and U.S. Pat. No. 5,086,166 describe methods of processing oilseeds comprising solubilizing the proteins and separating the protein fraction by use of an ultrafiltration membrane.
By use of membrane isolation techniques, proteins are recovered from accompanying byproducts, in particular polysaccharides.
Methods of producing protein isolates by the combined action of carbohydrate degrading enzymes and separation techniques have never been described.